On Monday the Food and Drug Administration (FDA) decided to halt all imports of orange juice into the U.S. after a juice manufacturer alerted the agency to small amounts of an illegal fungicide in both their products and those of competitors.

The decision immediately raised prices of orange juice futures, but left a more pressing question unanswered — is it safe to drink OJ?

According to the FDA, the Coca-Cola company, which makes Minute Maid and Simply Orange, notified the agency on December 28 that some Brazilian growers of oranges that are used in the company’s juices had sprayed their trees with carbendazim. Carbendazim is used in some countries to control a fungal infection in crop plants. “In the United States, however, the Environmental Protection Agency (EPA) has not approved carbendazim for use as a fungicide on oranges, nor has it established a tolerance or an exemption from the need for tolerance for carbendazim in orange juice in the United States,” wrote an FDA official in a letter to the Juice Products Association alerting the industry to the concern. About one in six glasses of orange juice consumed in the U.S. is produced by Brazil, according to CitrusBR, a Brazilian industry association.

The FDA is currently blocking all imported juices and inspecting them for the fungicide. While it’s not clear how dangerous the chemical is to human health, studies on animals show that high doses can lead to reduced fertility and still births in pregnant female mice and birth defects in their pups. The chemical can also trigger unhealthy cholesterol, triglyceride and glucose levels and drive hormone levels of estrogen and progesterone, important for reproductive health, down.

For now, the FDA says

The Environmental Protection Agency has conducted a preliminary risk assessment based on the recent reports of carbendazim in orange juice. Based on that risk assessment, EPA has concluded that consumption of orange juice with carbendazim at the low levels that have been reported does not raise safety concerns. FDA does not intend to take action to remove from domestic commerce orange juice containing the reported low levels of carbendazim. FDA is, however, conducting its own testing of orange juice for carbendazim, and, if the agency identifies orange juice with carbendazim at levels that present a public health risk, it will alert the public and take the necessary action to ensure that the product is removed from the market.

Why did it take a company, and not government screeners, to detect the fungicide? The FDA currently does not test for carbendazim because it wasn’t deemed a risk to human health, Siobhan DeLancey, a spokeswoman for the agency told Bloomberg.

Given recent cases of contaminants in imported foods, from fish to produce, and worries over arsenic in apple and grape juice, consumer groups are calling for greater inspection of foods imported and sold in the U.S. for potential toxins and pathogens.

For now, the FDA is refusing to allow juice for sale in the U.S. if it contains more than 10 parts per billion of carbendazim. For juices already on store shelves or in people’s homes, the limit is slighter lower, at 80 parts per billion because an EPA assessment shows that exposure at that level shouldn’t be a safety concern for consumers, an EPA official told Bloomberg. So far, the agency is not asking consumers to throw out any orange juice they already have.Alice Park is a writer at TIME. Find her on Twitter at @aliceparkny . You can also continue the discussion on TIME’s Facebook page and on Twitter at @TIME.